1. Field of the Invention
The present invention relates to a sheet conveyer and a printer fitted with a sheet conveyer.
2. Description of the Related Art
The assignee's Japanese Patent Application No. 8-30814 discloses an ink jet printer, which includes a feed roller and pressure rollers in compressive contact with the feed roller. The pressure rollers are supported by holders. A sheet passage is formed between each of the holders and a passage wall positioned upstream from the feed roller. The passage wall inclines toward the holders. Whichever of the passage wall and the holders a sheet of paper is fed along, the front end of the sheet is guided or led finally along the holders securely to the lines of contact each between the feed roller and one of the pressure rollers.
If a sheet of paper is fed along the passage wall, and when the front end of the sheet is sent between the feed roller and the pressure rollers, the sheet turns or bends sharply at the front end of the wall toward the lines of contact between the rollers. This causes high resistance to the feeding. In particular, an envelope, a post card or another paper sheet of higher rigidity does not easily bend, and therefore the resistance to it is higher, hindering the feeding. Therefore, the front end of the passage wall might be spaced as away as possible from the feed roller so that a sheet of paper bends gently at the wall end. By the way, as shown in FIG. 8 of the drawings accompanying this specification, it is not avoidable that the front end of a sheet S being fed is largely wavy up (S2) and down (S1) over the width of the sheet. If the passage wall and the feed roller were spaced wide from each other, the valley/s of the sheet wave might meet the cylindrical surface of the feed roller nearly radially of the roller. As a result, the sheet might be damaged. In particular, the damage is serious if the wave valley/s meets/meet the feed roller turning reversely (in the direction opposite to the feeding direction) to register the sheet end. It is therefore not possible to make the space between the passage wall and the feed roller very wide.